1x 3ware controllers vs. 2x 3ware controllers

I'm looking at building what I guess you could call a budget NAS
array.  I'm looking to start with four 250MB SATA drives on 3ware
8506-4LP controller.  I eventually want to move to eight drives in the
box.  Is there any reason to expect that the performance of eight
drives spread across two 8506-4LP controllers is going to be any worse
then the same eight drives all on one 8506-8?

--adam